I’ve been using this for quite a long time. The main selling point is to filter out search results, and it does it fine; it doesn’t prevent access to the site by e.g. manually typing the URL. For the later, as another poster said, uBlock Origin works better.

(Funnily enough I installed it because of Reddit. When I want an answer I want an answer, not a bunch of parrots repeating the same stale jokes, the same “I dun unrurrstand”, vomiting trivia or crap like this.)

Any options that could work with duckduckgo?

This hardly offers new functionality. The same thing can be achieved Preventing entering a website can be achieved via My filters in uBlock Origin - all you need to do is type there the domain of the website, one per line, e.g. ||reddit.com and click Apply changes.

And from screenshots of the addon linked here it looks like it’s limited to blocking domains that are shown in google search results? That would be much more limited than using uBlock Origin.

Edit: Oh, I’ve looked at the screenshots again and I see the difference - the blocked domain disappeared from the search results. So yeah, it’s useful functionality for people who use google.